The present invention relates to a steering wheel for vehicles, provided with so-called self-aligning structure, wherein when impact load acts on a rim, the rim surface is slanted in approximately perpendicular direction with respect to the line of action of the impact load. More specifically, the self-aligning structure is constituted in that a self-aligning plate (connector) comprising a boss fitting portion, a spoke fitting portion and a plurality of plastically deformable arm portions arranged in an annular space formed between both fitting portions, is arranged between an assembled body of rim/spokes and a boss. When impact load acts on the rim, the rim surface is slanted in approximately perpendicular direction with respect to the line of action of the impact load due to plastic deformation of the plastically deformable arm portions.
Such a steering wheel in the prior art is disclosed, for example, in Japanese U.M. application laid-open No. 9764/1985 (refer to FIGS. 1.about.3). In this example, five plastically deformable arm portions 15 each having a curved portion 15a at intermediate portion are arranged in radial direction between an annular boss fitting portion 5 and a spoke fitting portion 7 with respect to three spokes 11, and a self-aligning plate (connector) 9 with the plastically deformable arm portions 15 are arranged between a boss 3 and an assembled body of rim 13/spokes 11.
When load acts on the rim 13 of the steering wheel (FIG. 2), surface of the rim 13 is slanted in approximately perpendicular direction with respect to the line of action (FIG. 3, hereinafter referred to as "self-aligning function").
On the other hand, demand of a steering wheel of two-spoke type is increasing due to request from the view point of design.
In order to apply to the self-aligning plate 9 with the five plastically deformable arm portions 15 of the prior art to the above-mentioned steering wheel of two-spoke type (refer to FIG. 1), since stress concentration is apt to occur particularly at edge portion of the boss fitting portion 5 in the intersection position between the two plastically deformable arm portions 15 near both spokes 11, chamfering or annealing must be applied to the intersection position so as to provide the durability. In other words, if the working accuracy is not increased in the intersection position between the two plastically deformable arm portions 15 near the spokes 11, sufficient durability cannot be maintained. That is, the self-aligning plate 9 is usually manufactured by means of press punching, and, during the manufacturing, accuracy of a press cutting edge or a setting jig must be increased and burr removing finishing after the punching must be performed carefully.